Field of the Invention
The present invention relates to a rectangular secondary battery including a circuit breaker and a method of making the same.
Description of Related Art
Development of secondary batteries for use as power sources of vehicles, such as electric vehicles (EV) and hybrid electric vehicles (HEV, PHEV), or the like is underway. Because high capacity and high power are required for vehicle power sources or the like, a plurality of secondary batteries that are connected in series or in parallel are used. In view of space efficiency, rectangular secondary batteries are used as such secondary batteries.
A very high level of safety is required for secondary batteries for such use. Therefore, as described in Japanese Published Unexamined Patent Applications No. 2008-066254 (Patent Document 1), Japanese Published Unexamined Patent Applications No. 2008-066255 (Patent Document 2), and Japanese Published Unexamined Patent Applications No. 2010-212034 (Patent Document 3), some secondary batteries include a gas discharge valve for reducing internal pressure when the pressure in a battery housing increases, and a circuit breaker for breaking an electrical connection between an electrode body and a terminal.
For rectangular secondary batteries including a circuit breaker, it is required that the circuit breaker be immediately activated to break an electrical connection between the electrode body and the terminal if the pressure inside the battery reaches a predetermined value.